// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2014-2015 Benoit Steiner <benoit.steiner.goog@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#include "main.h"

#include <Eigen/CXX11/Tensor>

void
test_signed_32bit()
{
	// Divide by one
	const Eigen::internal::TensorIntDivisor<int32_t, false> div_by_one(1);

	for (int32_t j = 0; j < 25000; ++j) {
		const int32_t fast_div = j / div_by_one;
		const int32_t slow_div = j / 1;
		VERIFY_IS_EQUAL(fast_div, slow_div);
	}

	// Standard divide by 2 or more
	for (int32_t i = 2; i < 25000; ++i) {
		const Eigen::internal::TensorIntDivisor<int32_t, false> div(i);

		for (int32_t j = 0; j < 25000; ++j) {
			const int32_t fast_div = j / div;
			const int32_t slow_div = j / i;
			VERIFY_IS_EQUAL(fast_div, slow_div);
		}
	}

	// Optimized divide by 2 or more
	for (int32_t i = 2; i < 25000; ++i) {
		const Eigen::internal::TensorIntDivisor<int32_t, true> div(i);

		for (int32_t j = 0; j < 25000; ++j) {
			const int32_t fast_div = j / div;
			const int32_t slow_div = j / i;
			VERIFY_IS_EQUAL(fast_div, slow_div);
		}
	}
}

void
test_unsigned_32bit()
{
	for (uint32_t i = 1; i < 25000; ++i) {
		const Eigen::internal::TensorIntDivisor<uint32_t> div(i);

		for (uint32_t j = 0; j < 25000; ++j) {
			const uint32_t fast_div = j / div;
			const uint32_t slow_div = j / i;
			VERIFY_IS_EQUAL(fast_div, slow_div);
		}
	}
}

void
test_signed_64bit()
{
	for (int64_t i = 1; i < 25000; ++i) {
		const Eigen::internal::TensorIntDivisor<int64_t> div(i);

		for (int64_t j = 0; j < 25000; ++j) {
			const int64_t fast_div = j / div;
			const int64_t slow_div = j / i;
			VERIFY_IS_EQUAL(fast_div, slow_div);
		}
	}
}

void
test_unsigned_64bit()
{
	for (uint64_t i = 1; i < 25000; ++i) {
		const Eigen::internal::TensorIntDivisor<uint64_t> div(i);

		for (uint64_t j = 0; j < 25000; ++j) {
			const uint64_t fast_div = j / div;
			const uint64_t slow_div = j / i;
			VERIFY_IS_EQUAL(fast_div, slow_div);
		}
	}
}

void
test_powers_32bit()
{
	for (int expon = 1; expon < 31; expon++) {
		int32_t div = (1 << expon);
		for (int num_expon = 0; num_expon < 32; num_expon++) {
			int32_t start_num = (1 << num_expon) - 100;
			int32_t end_num = (1 << num_expon) + 100;
			if (start_num < 0)
				start_num = 0;
			for (int32_t num = start_num; num < end_num; num++) {
				Eigen::internal::TensorIntDivisor<int32_t> divider = Eigen::internal::TensorIntDivisor<int32_t>(div);
				int32_t result = num / div;
				int32_t result_op = divider.divide(num);
				VERIFY_IS_EQUAL(result_op, result);
			}
		}
	}
}

void
test_powers_64bit()
{
	for (int expon = 0; expon < 63; expon++) {
		int64_t div = (1ull << expon);
		for (int num_expon = 0; num_expon < 63; num_expon++) {
			int64_t start_num = (1ull << num_expon) - 10;
			int64_t end_num = (1ull << num_expon) + 10;
			if (start_num < 0)
				start_num = 0;
			for (int64_t num = start_num; num < end_num; num++) {
				Eigen::internal::TensorIntDivisor<int64_t> divider(div);
				int64_t result = num / div;
				int64_t result_op = divider.divide(num);
				VERIFY_IS_EQUAL(result_op, result);
			}
		}
	}
}

void
test_specific()
{
	// A particular combination that was previously failing
	int64_t div = 209715200;
	int64_t num = 3238002688ll;
	Eigen::internal::TensorIntDivisor<int64_t> divider(div);
	int64_t result = num / div;
	int64_t result_op = divider.divide(num);
	VERIFY_IS_EQUAL(result, result_op);
}

EIGEN_DECLARE_TEST(cxx11_tensor_intdiv)
{
	CALL_SUBTEST_1(test_signed_32bit());
	CALL_SUBTEST_2(test_unsigned_32bit());
	CALL_SUBTEST_3(test_signed_64bit());
	CALL_SUBTEST_4(test_unsigned_64bit());
	CALL_SUBTEST_5(test_powers_32bit());
	CALL_SUBTEST_6(test_powers_64bit());
	CALL_SUBTEST_7(test_specific());
}
